Iain and Dawn Askham tested positive after their honeymoon in Mexico
The newly-weds who were the UK's first swine flu cases have spoken of how they feared they might die from the virus.
Iain Askham, of Polmont, near Falkirk, told the Daily Mail: "You try to stay calm but at the back of your mind there is the possibility that you might die."
He and wife Dawn believe they caught the virus on a flight back from Mexico.
Test results will reveal later whether a friend of theirs is the first person in the UK to have contracted the virus without having visited Mexico.
The man was named by the Daily Mail as Graeme Pacitti, 24, who it said had been in contact with Mr Askham after their honeymoon.
He has been referred to as a "probable" case by Scottish Health Secretary Nicola Sturgeon.
So far eight swine flu cases have been confirmed in the UK but this would represent the first case of onward transmission of the virus within the country.
Ms Sturgeon said: "Obviously the circumstances around this individual do give us cause for concern - the symptoms don't give us cause for concern, but the circumstances give us cause for concern."
Mr and Mrs Askham returned to their home on Thursday having been treated for five nights in separate isolation rooms at Monklands Hospital, Airdrie.
"It was particularly hard to bear, because I knew that Dawn was next door and that she wasn't well," Mr Askham told the newspaper.
"She was so close and yet I could not reach her. I just wanted to give her a cuddle and reassure her."
The couple said they believed they contracted the virus on their flight back from Cancun, during which several passengers were coughing and sneezing.
The latest Britons to return from Mexico, about 300 people on a scheduled Thomas Cook flight, arrived at Gatwick on Friday morning.
Passengers told the BBC no one's temperature was taken - which differed from the screening process in the Mexican resort of Cancun - despite indications by the British government there would be enhanced health checks at UK airports.
Of the eight cases confirmed in the UK so far, three are in London, there has been one each in Newcastle upon Tyne and Redditch, Worcestershire, and a 12-year-old girl has tested positive in Paignton, Devon.
Graeme Pacitti (right) and Mr Askham play for the same football team
All of those diagnosed are thought to have responded well to treatment.
A total of 230 possible cases are being investigated in the UK.
Dr Alan McNally, senior lecturer and influenza diagnostics researcher at Nottingham Trent University, downplayed the significance of the suspected case linked to the Askhams.
"We know that [the flu] is transmitted from human to human, it has happened in other parts of the world and we know it will happen here.
"I know that there will be interest in it because members of the public will see that they don't need to have been to Mexico to get it."
Cases of swine flu have been confirmed in 12 countries across three continents.
CONFIRMED & SUSPECTED CASES
Mexico: 168 suspected deaths, 12 confirmed
US: one death, at least 109 confirmed cases
New Zealand: 4 confirmed, 12 probable cases
Canada: 34 confirmed cases
Spain: 13 confirmed cases
UK: 8 confirmed cases
Germany: 3 confirmed cases
Israel, Costa Rica: 2 confirmed cases each
Netherlands, Switzerland, Austria: 1 confirmed case each
Precautions being taken in the UK include enhanced airport checks, an expansion of anti-viral stocks from 35 million to 50 million by the end of May, the ordering of extra face masks and delivery of information leaflets for every family.
Supplies of antibiotics are to be increased to deal with any complications arising as a result of flu infections.
An advertising campaign to help prevent the spread of the virus has also been launched.
The Department of Health's Catch it, Bin it, Kill it! adverts urge people to cover coughs and sneezes with tissues, throw them away and wash their hands.
Meanwhile, the WHO has announced it will call the virus influenza A (H1N1), rather than swine flu, which it says is misleading as pork meat is safe and the virus is being transmitted from human to human.
Members of the public can call 0800 1513513 for recorded information about swine flu. In Scotland, anyone with concerns about the virus can call 08454 24 24 24.
An advertising campaign urges people to catch the sneeze before binning the tissue
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